Review: Bought a bike off a guy and my cleats didn't match the pedals installed. I decided it would be easier to swap the cleats out on my shoes than attempt to break loose years of use and abuse without a proper pedal wrench.
Walked in and quickly found the shoes/cleats and started looking. Finally found what I needed (understaffed and quite busy for a Sunday afternoon) and brought the bike in to double check measurements. While I didn't get asked if I needed help, no one batted an eyelash at the guy hauling a Trance X2 into the store.
As I was paying for my cleats, the woman behind the register even added some helpful information that I had failed to remember (pedals have specific thread directions) and was very nice.
Without a doubt, I'd head back to Performance Bicycle. They had plenty of tires on the shelves, racks of tubes, tons of bikes of all shapes and sizes, helmets, shoes, lights, electronic bits, and a host of other bike parts. If you are in the southern Montgomery County area, check out Performance Bicycle on Rockville Pike.